birthday depression

how do you cope with birthday depression? i’m turning 16 on monday 5/13 and for the last week my anxiety has been awful and i’ve been more sad than usual. birthdays just make me feel like a disappointment. i hate them. i hate not being able to feel happy on them because i’m depressed. also, this is my first birthday after my suicide attempt which is really hard on me right now. what do i do... why are anniversaries and holidays such triggers?